Cold rolling mills



och 1959 YOSHIHIKO MURAKAMI 2,907,235

COLD ROLLING MILLS Filed April 24, 1956 2 Sheets-Sheet 1 l l I I I I l l l Oct. 6, 1959 Filed April 24, 1956 YOSHIHIKO MURAKAMI COLD ROLLING MILLS 2 Sheets-Sheet 2 Y m r United States Patent COLD ROLLING MILLS Yoshihiko Murakami, Mama-.cho, Ichikawa City, Japan Application April 24, 1956, Serial No. 580,326 Claims priority, application Japan June 15, 1955 2 Claims. (Cl. 8038) The present invention relates to an improvement of 4- high type cold rolling mills and, more specificially, to the roll-assemblies of cold rolling mills.

In the conventional type of 4-high mill for the cold rolling of'metal strip or metal sheets, power is supplied by directly driving the work rolls and his impossible to make the diameter of the work rolls smaller than a certain limit because of the problem of strength. Mills which utilize the drive of the backing rolls have the disadvantage of necessitating too many complications in construction as well as inconvenience in the adjustment of rolls owing to the complex device supporting the work rolls. Heretofore, various ideas have been considered in order to eliminate the foregoingdrawbacks, but so far no successful results have been attained.

Furthermore, even in rolling sheets and strip with the complicated cluster type mill, it has been impossible to avoid uneven elongation and thickness of the metal. To overcome this defect, work rolls of conventional mills have been invariably designed with a fixed crown, so that In order to achieve the above described objects, 1 provide a mill such that a pair of cylindrical type-work rolls without journals are driven by a pair of back up rolls (intermediate rolls) provided on the top and bottom thereof. 1 also provide many supporting rollers in contact with both inlet and delivery sides of the work roll faces and by making the backing rollers contact the circumferential face of the back up rolls at several points. The back up-rolls and possibly the work rolls are given a fixed strainvbeforehand by imposing a fixed pressure to these supporting rollers.

Other advantages and objects of the present invention are described in the following. detailed description as illustrated by the annexed drawings showing a preferred embodiment of the invention. In the drawing-2,

Fig. 1 is an elevation sectional view ofa preferred type r of rolling mill according to the present invention.

Fig. 2 is a vertical sectionof the housing ofthe rolling mill illustrated in Fig. 1.

Fig. 3 is an enlarged detail of the'supporting mecha- V nism for the work rolls of. the rolling mill illustrated in Fig. 2.

Fig. 4 is a partial plan view of Fig. 3, showing a partial cross section;

Fig. 5 is a detailed drawing showing diagrammatically the relation with avfixed strain curve given to the work rolls by the backing rollers..

In the millshown in Fig. 1, the power generated by the motor I mounted on the motorbase 2 is transmitted to a lower back up (intermediate) roll 8 and upper back up (intermediate) roll9 through, the. motor coupling 3,. difat a certain rolling pressure. It is impossible, however, to compensate the strain on a work roll when the rolling pressure varies according to the metal being rolled and the percentage of reduction. Further, in the cluster type mill such as the so-called Sendzimir mill, the housing containing the back up rolls per se is an element that absorbs the rolling pressure; consequently, despite the fact that a substantially precise machining is employed, the strain of the various parts are aggregated thus causing an unstable strain on the whole, which is diflicult to compensate.

According to the present invention, the abovementioned defects are completely eliminated. Accordingly, one object of the present invention is to make the diameter of the work roll smaller and the reduction greater while using the same motive power; there results an improved rolling mill which produces extremely flat products of superior quality and exerts rolling pressure over the entire longitudinal roll surface.

Another object of the present invention is to simplify supporting devices used for work rolls and the replacement of the Work rolls.

Another object of the present invention is to provide a great number of replaceable supporting rollers which are provided on both faces of thework rolls in contact with the circumferential surface of the work rolls and thereby simplify replacementof the work rollsand also prevent the work rolls from slipping off horizontally.

A feature of thepresent invention is to place-the-backing rollers in contact with the circumferential faces of a pair of back up rolls at several points and then apply a fixed pressure to the backing rollers and pro-stress the back up rolls and possibly the work rolls. This makes it possible to obtain products having uniform thickness by controlling the strain put on the upper work rolls and lower work rolls by the rolling pressure.

ferential gear group 5 provided in gear box 4,- spindle couplings 6 and spindles 7. Theupper back up (intermediate) roll 9 and lower back up (intermediate) roll 8 drive the work rolls 10 and are. supported rotatably by an upper chock 14 and lower chock 15. mounted in housing 11. Guide blocks 25 and 27 are. provided on the housing to restrict movement of rolls 8 and 9 in a longitudinal direction. The work rolls 10 which are driven by rolls 8 and 9 and which are mounted rotatably in housing 11 between rolls 8 and 9 are of acylindrical type without journals. Many supporting rollers 20 are rotatably supported by shafts 23 on supporting brackets fixed by bolts 22 to the housing 11. Rollers 20 are positioned against the work roll faces at both the delivery andinlet sides of the metal passage. Rollers 20 are spaced by rigid supports 21 which engage shaft 23 to prevent deflection thereof. The fact that I: have made these supporting rollers numerous enables-the reduction of the diameter of. the work rolls 10. Furthermore, guide blocks 26 are. provided on the housing 11 to restrict. longitudinal slip.- page of the work rolls 10.

The upper backing roller 12 mounted between bearing boxes 13 touches. the top face of the abovementioned upper intermediate roll 9 and pressure is transmitted. to. the top face of the upper intermediate roll 9 through the upper backing roller 12 by means of. the housingscrewvs 19 which pass through the top wall of the housing, 11. Pressure is also transmitted to the journals, of the upper intermediate roll 9 through the upper roll chocks 14. by. means of said screws. This pressure is thereby transmitted to the upper work roll 10 and gives the roll 10 a strain curve asdesired. Guide blocks24 serve to restrict horizontal slippage ofthe upper backing. roller 12.

a fixed strain so that the strain curve of said roll 8 and lower work roll 10 will correspond to that of the upper work roll. Guide block 28 mounted on the housing 11 restricts horizontal slippage of bearing boxes 17 and 18 and lower backing rollers 16.

In operating the rolling mill of the present invention, a desired rolling pressure can be obtained by turning the housing screws 19 to a desired position and giving a suitable downward pressure to the upper backing roller 12 and, at the same time, desired strain curves are thereby imparted to the upper and lower work rolls 1t 10.

As illustrated in Fig. 5, upper intermediate roll 9 is pressed downward by upper backing roller 12 at 12' and upper chocks 14 at 14a and 14b respectively, and the lower intermediate roll 8 is pressed upward by the lower backing rollers 16 at 16' and 16b. Rolls 9 and S and thus upper work roll and lower work roll 10 form strain curves as indicated respectively by figures g and 4), and can be regulated to roll products of uniform thickness.

By switching on the motor after completing the above described operation, the upper and lower intermediate rolls 8 and 9 will start to rotate and subsequentlydrive the work rolls 10, thus producing a metal of uniform thickness which will give a uniform rolling pressure to the metal passing between them. In this case, the difien ential gear group 5 rotates the upper and lower intermediate rolls 8, 9 and subsequently drives the work rolls. Therefore, there is no necessity of making the diameters of the upper and lower intermediate rolls 8, 9 and work rolls 10, of equal size as required in conventional 4-high type rolling mills. Even if there should be some variations between the diameters of the respective rolls, the rolling operation can be smoothly effected.

In summary, the invention provides, in accordance with a preferred embodiment thereof, a 6-high straight type cold rolling mill comprising lower and upper intermediate driving back-up rolls 8 and 9 with a pair of work rolls 10 between and driven by frictional engagement with rolls 8 and 9. A single relatively narrow upper backing roll 12 bears downwardly on roll 9 at the center of the latter. Roll 12 constitutes the sole backing support for the upper back-up roll 9 and performs this backing function in localized manner over a narrow portion at the center of roll 9.

Two lower backing rolls 16 are disposed below lower back-up roll 8 and constitute the sole backing support for roll 8. The lower backing rolls are spaced by a distance substantially equal to the width of roll 12 and the space between rolls 16 is aligned vertically with roll 12. This gives a wavy stress to the back-up and working rolls, as shown in Fig. 5.

Side supporting assemblies including elements 2l23 are disposed at the inlet and outlet sides of work rolls 10 and horizontally support the work rolls along their entire lengths. The side supporting assemblies include spacedapart rollers 20 and rigid support means including elements 21.

In a preferred embodiment of the invention, the lower rolls 16 are spaced by approximately one-quarter of the length of the lower roll 8 at the center of the latter, and the upper backing rolls are adjustable whereas the lower rolls are fixed.

The present invention, of course, is not limited to the above described example, and various modifications are conceivable within the scope of this invention.

I claim:

1. A 6-high straight type cold rolling mill comprising upper and lower intermediate driving back-up rolls, a

4 1 pair of work rolls disposed between said back-up roll and driven by frictional engagement with the latter, a single relatively narrow upper backing roll bearing downwardly on said upper back-up roll at the center of the latter and constituting the sole backing support for said upper back-up roll localized over a narrow portion at the center thereof, two lower backing rolls disposed below said lower back-up roll and constituting the sole backing support for the latter, said lower backing rolls being spaced a distance substantially equal to the width of said narrow backing roll, with the space therebetween aligned vertically with said narrow backing roll to thereby give a wavy stress to said back-up and working rolls, and

a side supporting assemblies disposed at the inlet and outlet sides, respectively, of each of said work rolls and horizontally supporting the latter along the entire length of the work rolls; each of said side supporting assemblies including a shaft, 2. series of spaced-apart rollers having diameters slightly smaller than that of the related work roll and rotatably mounted on said shaft, each shaft beingspaced substantially horizontally from the associated work roll, and rigid support means for said shaft engaging the latter in each of the spaces between the series of rollers, thereby to prevent deflection of said shaft and, hence, of the related work roll.

2. A 6-high straight type cold rolling mill comprising upper and lower intermediate driving back-up rolls, a pair of work rolls disposed between said back-up rolls and driven by frictional engagement with the latter, a. single relatively narrow upper backing roll bearing downwardly on said upper backup roll at the center of the latter, two lower backing rolls disposed below said lower back-up roll and supporting the latter, and side supporting assemblies disposed at the inlet and outlet sides, respectively, of each of said work rolls and horizontally supporting the latter along the entire length of the work rolls, said rolling mill further comprising a frame, journals at the opposite ends of said upper back-up roll, adjustable means supporting said journals from said frame to accept a part of the upward rolling pressure, adjustable means supporting said single upper backing roll from said frame to accept the remainder of the upward rolling pressure, said two lower backing rolls being relatively narrow and disposed at positions spaced by approximately one-quarter the length of said lower back-up roll from the center of the latter, and fixed means supporting said lower backing rolls on said frame to accept all of the downward rolling pressure so that said adjustable means supporting the journals of said upper back-up roll and said upper backing roll and said fixed means supporting the lower backing roll cooperate to control the adjustment of the gap between said work rolls.

References Cited in the file of this patent UNITED STATES PATENTS 1,688,335 Iverson Oct. 23, 1928 1,824,211 Jobke Sept. 22, 1931 1,870,509 Heiden Aug. 9, 1932 1,905,129 Biggert, Jr. et al Apr. 25, 1933 1.953.190 Paterson Apr. 3, 1934 1,964,893 Rohn July 3, 1934 2,181,173 Catulle Nov. 28, 1939 2,187,250 Sendzimir Ian. 16, 1940 2,271,459 McConnell Ian. 27, 1942 FOREIGN PATENTS 311,142 Germany Feb. 27, 1919 

